Old Muscle-Control (image) University of California - Berkeley Caption As muscle tissue ages, it loses its ability to adequately repair itself from damage. Instead of creating healthy, new cells to replace damaged ones, the old muscle tissue is left with fibroblasts and scar tissue, as shown here. Credit Photo courtesy of Morgan Carlson and Irina Conboy, UC Berkeley Usage Restrictions Must include credit to Morgan Carlson and Irina Conboy, UC Berkeley Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.